Grease interceptor level analyzer

ABSTRACT

An analyzer for a grease interceptor for measuring levels of fat, oils, and grease (FOG), water, sludge and air having a probe which includes a controller and a sensor sub-unit. Sensor circuits include a microcontroller, timers, and sampling capacitors. The sensor sub-unit includes a plurality of electrode ring pairs coupled to a plurality of timers for converting capacitance measurements to frequencies under the control of a microprocessor in the controller. The frequencies identify the measured levels.

RELATED APPLICATIONS

This Nonprovisional Patent Application claims the benefit of U.S.Provisional Application For Patent No. 62/786,801, filed Dec. 31, 2018,the complete subject of which is herein incorporated by reference intheir entirety for all purposes.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates generally to a grease interceptor or grease trapused where food is handled and served and in particular to a greaseinterceptor level analyzer for measuring the levels of fats, oils,grease, and sludge within the interceptor.

Description of Related Art

Grease interceptors, or grease traps, are required in all food serviceestablishments (FSE). These include commercial kitchens, food service,food preparation and other facilities where food is handled and servedto prevent fats, oil, and grease and solids/sludge from entering thesanitary sewer or septic system where it leads to blockages andcontamination. Fats, oil, and grease are referred to as FOG and withsolids as FOGS.

Grease traps refer to above ground tanks usually located in or near thekitchen. Grease interceptors refer to large in-ground outdoor tanks. Theterms traps and interceptors are used interchangeably herein.

Referring to FIG. 1, a graphic illustration of a typical passive greaseinterceptor 10 in the prior art is show. Conventional greaseinterceptors are passive and rely on the specific gravity of thecomponents of the wastewater 12 to separate. The wastewater 12 entersthe trap and is typically piped to below the midpoint where it emptiesinto the trap. The FOG 14 is lighter than water and floats to the top.Solids 18 settle to the bottom as sediment (or “sludge”). This creates astatic level of liquids made up of 3 layers: sediment 18, water 12 andFOG 14. The water 12 portion exits the grease trap so that the totallevel of all three layers remains constant and the FOGS layers 14, 18grows. The interceptor 10 must be emptied before the FOG 14 layerreaches the outlet 19 for the water. Municipalities regulate themaintenance of grease interceptors. One common regulation requiresemptying the trap when the volumes of the FOG 14 plus solids layersreach 25% of the total volume.

The traditional core sampler, aka “Sludge Judge”, requires opening up aninterceptor, sticking in the sampler, waiting for the contents to settleand taking measurement with a ruler. It's dirty, smelly andtime-consuming. It cannot be automated and cannot be adapted to makereal-time measurements. Though the upfront cost is low (approximately$200) the time required to conduct the measurement and clean and travelfrom site to site make the operating costs very high. Furthermore, themanual operation of this device prevents it from being automated.

The leading technology for electronic measurement of FOG levels is basedon measuring layer interfaces using an ultrasonic transducer andreceiver. This device fouls easily and is frequently “confused” byspurious reflections, such as walls and foam. The last drawback limitsthe use of ultrasonic analyzers to large interceptors. The majority ofgrease traps in restaurant kitchens are therefore unable to availthemselves of this technology. The underlying ultrasonic technologymakes this device necessarily expensive and complex.

At least one commercialized FOG analyzer used the principle ofresistivity to measure differences between FOG, water and sediment. Thismethod is intrinsically simple and inexpensive. However, this type ofdevice\ works only when the surfaces of the measuring electrodes areclean. In practice the oily environment of a grease trap quickly coatsthe electrodes and decreases the measured resistivity.

The capacitance-based FOG analyzer has distinct advantages over theabove prior art such as: providing real-time level measurements,requiring only periodic opening of the grease traps when they are beingserviced, providing a read-out that is easy to understand, results canbe sent automatically to a networked server, cost is lower thancompeting ultrasound-based analyzers, it is less susceptible to foulingthan ultrasound-based analyzers, and it can be easily assembled to fitinto any grease interceptor from small kitchen units to large outsideones.

In the prior art, U.S. Pat. No. 8,943,911 issued Feb. 3, 2015 to Mark C.Terrell discloses a system for remotely monitoring stratified layers ingrease interceptors including a sensing unit for being disposed in agrease interceptor having an elongated sensing rod and a plurality ofspaced apart sensors in groups along the rod for sensing stratifiedlayers in she grease interceptor, a wireless transmitter electricallycoupled to the sensing unit and a central server for receiving acquireddata transmitted by the wireless transmitter. However, the criticalelement in an accurate and successfully operating probe or monitor ofstratified layers of the grease interceptor is the sensor. Terrell etal. does not teach or disclose an operational sensor such as the novelsensor of the present invention, and in fact opines that substantiallyany type of sensor that right now exists or hereafter be discovered maybe used. Terrell does suggest use of sensors disclosed in U.S. Pat. Nos.6,619,118 and 6,879,935.

U.S. Pat. No. 6,619,118 Issued Sep. 16, 2003 to James C. Kech disclosesa septic tank monitoring system for distinguishing between andidentifying the location of a sedmentary layer, a scum layer and anyintervening liquid zone in a septic tank with an elongated sensing probefor being disposed in the septic tank. It discloses sensors that arerelatively small, hemispherical electrode, or it could preferably be aring electrode. However it does not disclose the accurate sensorstructure of the present invention.

U.S. Pat. No. 6,879,935 issued Apr. 12, 2005, also to James C. Kechdiscloses a monitoring system for a septic tank to distinguish betweenand identifying a sedimentary layer, a scum layer, and any interveningliquid zone in a septic tank with an elongate sensing probe formeasuring the differences in the layer's high frequency electricalconductivity using a plurality of sensors. It shows a common electrodereference sensor is disposed on the elongated tube of the probe andcould be a hemispherical electrode or a ring electrode. The othersensors spaced along the elongated tube are hemispherical, chemicallyinert sensor electrodes. However, the more accurate capacitance—basedsensor structure of the present invention is not disclosed.

U.S. Pat. No. 8,215,166 issued Jul. 10, 2012 To J. Vern Cunningham etal. disclosed a capacitance-based FOG analyzer having a grease sensorand remote monitor unit. However, in actual use the device wasinsufficient to reliably detect the positions of the FOG-water andwater-sludge interfaces.

SUMMARY OF THE INVENTION

Accordingly it is therefore an object of this invention is to provide agrease interceptor level analyzer for measuring levels of fats, oils,grease (FOG), water, sludge and air, this analyzer being embodied as afixed probe and a portable probe.

It is another object of this invention to provide a sensor sub-unit inthe analyzer, positioned in a circular arrangement to form plates of acapacitor, having a plurality of electrode ring pairs coupled to aplurality of timers for converting a capacitance measurement to afrequency and subsequently to identify the levels of FOG, water, sludgeand air from the collection of frequencies from the sensor sub-unit.

It is a further object of this invention to provide an interceptor levelmeasurement in real time from an analyzer to a food serviceestablishment to minimize the need for opening and servicing greaseinterceptors, along with reducing the cost of maintaining them.

It is another object of this invention to provide a daisy chainarrangement of the sensor sub-unit in the analyzer for performingcapacitance measurement of FOG, water, sludge and air levels ininterceptors of various heights.

These and other objects are accomplished by an analyzer for measuringlevels of fats, oils, grease, (FOG) water, sludge and air in aninterceptor comprising, a probe having a first portion and a secondportion, the first portion of the probe comprises control means andcommunication means, the second portion of the probe comprises at leastone sensor sub-unit for measuring the levels of FOG, water, sludge andair in the interceptor, the sensor sub-unit comprises a plurality ofelectrode ring pairs positioned adjacent to each other, a plurality oftimers, each of the timers being coupled to each of the electrode ringpairs respectively in the sensor sub-unit for converting a capacitancemeasurement of each of the electrode ring pairs to a frequency, and acontroller, included in the control means of the first portion of theprobe, being coupled to each frequency output of each of the timers fordetermining the levels of FOG, water, sludge and air in the interceptor.The analyzer comprises a microcontroller in the sensor sub-unit and inresponse to the controller enables the capacitance measurements to bemade in a sequential manner by each of the timers connected to each ofthe electrode ring pairs. The first portion of the probe comprises anenclosure into which the second portion is secured. The electrode ringpairs are positioned within the sub-unit immediately adjacent to aninside surface of the enclosure. Each of the electrode ring pairscomprises two adjacent copper strips sandwiched between sheets ofplastic and positioned within a sensor sub-unit in a circular formationforming plates of a capacitor, a dielectric of the capacitor beingformed by substances within an influence of an electric field generatedby the plates. The controller determines the FOG, water, sludge, and airlevels in the interceptor, and transmits the identity levels to anexternal receiver. The identity of materials including FOG, water,sludge and air at a level of each electrode ring pair is determined byan algorithm in a microprocessor of the controller. The algorithmdetermines the identity of the materials including FOG, water, sludgeand air at the level of each electrode ring pair from the value of thefrequency. The algorithm determines the identity of the materialsincluding FOG, water, sludge and air at the level of each electrode ringpair from a function of a range of frequencies of the electrode ringpair and adjacent electrodes. The analyzer comprises a fixed probe whenattached to the interceptor, and communicates identity of the FOG,water, sludge and air levels via a low frequency radio signal to areceiver. Also the analyzer comprises a portable probe for temporaryinsertion into the interceptor, and the portable probe communicatesidentity of the FOG, water, sludge and air levels via Bluetooth Le to anexternal device. The length of the probe is determined by the number ofthe sub-units daisy chained, one adjacent to another, each of thesub-units comprises a plurality of the electrode ring pairs coupled to aplurality of the timers and including a microcontroller for enabling thecapacitance measurement by each of the timers in a sequential manner.

The objects are further accomplished by a sensor sub-unit of an analyzerfor measuring levels of fats, oils, grease, (FOG) water, sludge and airin an interceptor comprising a plurality of electrodes positionedadjacent to each other in a circular arrangement, terminals of theelectrodes are attached to a printed circuit board (PCB) and positionedwithin the circular arrangement of the electrodes, a plurality of timerspositioned on the PCB, each of said timers receives an input from onepair of the plurality of electrodes forming a plurality of electrodering pairs; and the plurality of timers convert a capacitancemeasurement at each of the plurality of electrode ring pairs to afrequency. The electrodes comprise metallic electrodes. Amicrocontroller enables a readout of a capacitance measurementsequentially from an output of each the plurality of timers. Acontroller receives the capacitance measurement from each of theplurality of timers and determines an identity of the levels of FOG,water, sludge, and air in the interceptor. Each end of the sub-unitcomprises a means for connecting sensor sub-units in a daisy chainarrangement, one sub-unit connected to an adjacent sub-unit, forenabling the capacitor measurement to be made in a plurality ofinterceptors of varying heights.

The objects are further accomplished by a method for making an analyzerfor measuring levels of fats, oils, grease, (FOG) water, sludge, and airin an interceptor comprising the steps of providing a probe having afirst portion which comprises control means and communication means,providing a second portion of the probe having at least one sensorsub-unit for measuring the levels of FOG, water, sludge, and air in theinterceptor, positioning in the sensor sub-unit a plurality of electrodering pairs adjacent to each other in a circular arrangement, convertinga capacitance measurement of each of the plurality of electrode ringpairs to a frequency using a plurality of timers, each of the timersbeing coupled to each of the plurality of electrode ring pairsrespectively in the sensor sub-unit, determining an identity of thelevels of FOG, water, sludge and air in the interceptor using acontroller, the controller being included in the control means of thefirst portion of the probe coupled to each frequency output of each ofthe timers.

The method further comprises the step of enabling the capacitancemeasurement to be made in a sequential manner by each of the timersconnected to each of the electrode ring pairs using a microcontroller inthe sensor sub-unit and in response to a signal from the controller. Themethod comprises the step of positioning the electrode ring pairs withinthe sub-unit immediately adjacent to an inside surface of the firstportion of a probe. The method comprises the step of forming plates of acapacitor wherein each of the electrode ring pairs comprises twoadjacent metal strips sandwiched between sheets of plastic andpositioned within the sensor sub-unit in the circular arrangement, adielectric of the capacitor being formed by substances within aninfluence of an electric field generated by the plates. The methodcomprises the step of using the controller to determine an identity ofthe FOG, water, sludge, and air in the interceptor, and transmitting theidentity to an external receiver. The method comprises the step ofrepresenting by a range of frequencies received from the timer, theidentity of each of the FOG, water, sludge and air levels, and analgorithm in a microprocessor of the controller determines the FOG,water, sludge and air levels identity from the range of frequencies. Themethod comprises the step of determining the length of the probe by thenumber of the sub-units daisy chained, one adjacent to another, each ofthe sub-units comprises a plurality of the electrode ring pairs coupledto a plurality of the timers and including a microcontroller forenabling the capacitance measurement by each of the timers in asequential manner.

BRIEF DESCRIPTION OF THE DRAWINGS

The claims particularly point out and distinctly claim the subjectmatter of this invention. The various objects, advantages, and novelfeatures of this invention will be more fully apparent from a reading ofthe following detailed description in conjunction with the accompanyingdrawings in which like reference numerals refer to like parts, and inwhich:

FIG. 1 is a graphic illustration of a prior art grease interceptor tank.

FIG. 2 is a graphic illustration of a grease interceptor level analyzersystem according to the present invention.

FIG. 3 is a block diagram of capacitance measurement sensor circuits.

FIG. 4 is a schematic diagram of adjacent copper strips embedded inplastic used to form sensor electrodes of a sensor sub-unit.

FIG. 5 is a graphic cutaway illustration of a probe sensor sub-unit witheight pairs of circular sensor electrodes partially opened to show thesensor circuits printed circuit board.

FIG. 6 is a block diagram of a probe controller.

FIG. 7 is a flow chart of the method of FOG probe capacitancemeasurement sequence of operation according to the present invention.

FIG. 8 is a schematic diagram of the timer circuit in the sensor circuitof FIG. 3.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIG. 2, a block diagram of a capacitance—based greaseinterceptor level analyzer (GILA) system 20 is shown for providing inreal time fats, oils, grease (FOG), sludge and air level information inan interceptor 10 to a food service establishment (F SE), to anauthority having jurisdiction (AHJ) or to an interceptor servicecompany. The GILA system 20 including a probe 22, a probe sensorsub-unit 24, and a controller 26, is contained within an environmentallysealed container 28 such as a plastic pipe. The controller 26 transmitsmeasurement data to a gateway 30 via low frequency radio signal (LoRa)27. The gateway 30 transmits data to a cloud server and storage 32.Further the controller 26 communicates with a smart device 34 viaBluetooth LE (BLE) 29.

Still referring to FIG. 2, there are two embodiments of the probe 22, afixed probe 22 and a portable probe 23. The portable probe 23communicates via Bluetooth 29 to the smart device 34 and displays thelevels of FOG, water, sludge and air. It can also send data to the cloudserver and storage 32. This embodiment is made principally for municipalinspectors who enforce grease interceptor regulations. For the displayand storage of data in a portable probe 23, the user configures theprobe 23 through a wireless Bluetooth Low Energy (BLE) 29 connection. Anapp for both Android and iOS smart devices provides the user interfacefor configuring and viewing the probe 23 data.

The fixed probe 22 is permanently enclosed in a grease interceptor 30(FIG. 2) and communicates, via a low frequency radio signal (LoRa) 27 toa receiver gateway 30 on premises. The receiver, in turn, transmits datato a server and cloud-storage service 32. This embodiment is madeprincipally for FSE owners/operators and service companies that pump outthe interceptors.

In both embodiments of the probes 22, 23 the enclosure 28 is anenvironmentally sealed plastic pipe. Inside the probe 22, is a(replaceable) battery, a controller 26, a sensor sub-unit 24 having oneor more sensor circuits 40, each mounted on a PC board. The head boardwith the controller 26 is different for the two versions while the samesensor circuits 40 are used for both.

In FIG. 2, the GILA probe 22 makes periodic capacitance measurements todetermine the levels of FOG, water, sludge and air in a greaseinterceptor 30. The default period time is 15 minutes though the usercan change the frequency of readings. The probe 22 is powered by abattery so there is a trade-off between frequency of readings andbattery lifetime. At a 15-minute interval between, the battery lifetimeis approximately one year.

Referring to FIG. 3, a block diagram of sensor circuits 40 ₁ to 40 ₈ inthe probe 22 is shown. There are eight pairs of electrodes 42 connectedto eight timer circuits 46 ₁ to 46 ₈ that convert frequency tocapacitance, and the eight timer circuits 46 are sequentially activatedby a microcontroller 48 enable 50 output. As shown in FIG. 8, aschematic of the timer 46 is provided which measures the capacitance ofone of the copper electrode ring pairs 42. There is a timer 46 for eachsensor circuit 40 ₁-40 ₈ as shown in FIG. 3. The timer 46 ₁ to 46 ₈ maybe embodied by part no. LMC5551MX/NOPB well known in the art (See FIG.8). The microcontroller 48 may be embodied by Microchip part no.ATTINY828R-AURCT, commonly known in the art. The LDO 52 is a low dropout voltage regulator.

The output of each sensor circuit 40 ₁ to 40 ₈ is a square wave clocksignal with a frequency that is proportional to the capacitance of eachof the electrode ring pairs 42. The timer 46 operates in an astableconfiguration as shown in FIG. 8. A supply voltage Vcc of 3.3V causesthe timer to switch between high and low at a frequency that isproportional to the capacitance: f=1.44/[(R1+R2)×C]. The outputs of allsensor circuits 40 ₁ to 40 ₈, each on a small PC board, are wired to afrequency bus 49 that runs along the multiple sensor circuits 40 ₁-40 ₈on the PC board 60 (FIG. 5). Only one of the electrode ring pairs 42 isenabled at a time by the microcontroller 48 to provide a frequencyoutput from each timer 46.

The assembly of eight electrode ring pairs 42, the PC board 60containing the timers 46 ₁-46 ₈, and a microcontroller 48 compriseprimarily one sensor sub-unit 24 of the probe 22. Several sensorsub-units 24 can be daisy chained, one adjacent to another, to extendthe length of the probe 22 in increments of approximately 8 inches foruse in varying heights of interceptors 30. When the sub-unit 24 is thelower unit in a daisy chain configuration as illustrated in FIG. 5,there would be no connections to the terminals 59 in FIG. 5. Forexample, four sub-units 24 with four PC boards 60 (FIG. 5) containing atotal of 32 sensor circuits 40 make a probe 22 that will measure aninterceptor 30 approximately 32 inches high.

The microcontroller 48 connected to the sensor circuits 40 ₁-40 ₈,outputs each of the sensor frequency values in a sequential manner asdirected by the controller 26 (FIG. 6). The controller 26 collects thefrequencies generated by their timer circuits 46 ₁-46 ₈ and stores theresults. The key point is that the microcontroller 48 for the eightsensor circuits 40 ₁-40 ₈ controls the readout of the timer 46 ₁-46 ₈operating in an astable mode. In this mode the timer 46 outputs afrequency that is proportional to the capacitance of the electrode ringpair 42 formed by the parallel copper rings 56 (FIG. 4) that senses theinterceptor 30 medium.

There are two lines of communication between the sensor circuits 40 ₁-40 ₈ and the controller 26 (see FIG. 6). The Status Line T_(x) initiatesand terminates the capacitance measurement. The two values for theStatus Line are LOW and HIGH. The Frequency Line 49 transmits thecapacitance measurement to the controller 26 for storage and identity ofthe various levels within the interceptor 30.

The probe 22 includes a number of sensor-based printed circuit board(PCB) elements. Each sensor circuit 40 ₁-40 ₈ PCB comprises the timers46, and common electronic components, i.e. resistors, capacitors,buffers and LED's). The microcontroller 48 controls all switching andtiming functions of the sensor circuits 40 ₁-40 ₈.

Referring now to FIG. 4, a schematic of adjacent copper strips that formsensor electrodes 42 as shown for a sensor sub-unit 24 (FIG. 5) of theprobe 22. Two adjacent copper strips 52 and 54, are embedded in plastic55 and constitute one electrode pair 56. Eight pairs of electrodes 56are provided in one sensor sub-unit 24. The array of 16 copper stripsforming electrode ring pairs 42, has typical dimensions of height (H)4.7 inches, width (W) 0.5 inches of the copper strip, and the arraylength (L) 8.0 inches.

As described above, there is one dedicated sensor circuit 40 for eachcapacitance measurement. Each sensor circuit 40 ₁-40 ₈ contains acapacitor in the form of two parallel, thin copper electrodes 52 and 54in a circular formation. Capacitance values are made relative to water.Eight pairs of electrodes 56, spaced adjacent to each other, form eightelectrode ring pairs in one sensor sub-unit 24. The eight pairs ofelectrodes 56 are spaced at approximately one inch along the length ofthe probe 22. The entire array of eight pairs of thin copper stripelectrodes 56 are sandwiched between two sheets of clear plastic 55.

FIG. 4 shows the array of eight pairs of electrodes 56. Each copperstrip 52 has a terminal 57, for connections, to the timer 46 circuit.The timer circuits 46 ₁-46 ₈, each sequentially controlled by themicrocontroller 48, are mounted on a printed circuit board 60 andconnect to the sensor electrodes 42 ring pairs.

Referring to FIG. 5, a sensor sub-unit 24 of probe 22, comprises printedcircuit board (PCB) 60 positioned within the circular sensor electrodering pairs 42 which are opened up or cut away for illustration purposesin FIG. 5 to show the PCB 60 inside the plurality of rings of electrodes56. The microcontroller 48 can be seen in the center of the PCB 60. Eachof the eight timer circuits 46to 46 ₈ connect to one pair of electrodes56 located above the timer circuits. The pair of electrode rings 56 areconstructed from thin copper strips 52 sandwiched between sheets ofplastic 55 as shown in FIG. 4. When inserted into the enclosure 28(plastic pipe), the flexible sensor sub-unit 24 conforms to the interiorof the enclosure 28. As previously described any number of these sensorsub-units 24 can be connected together to create a probe 22 that is amultiple of eight sensor electrode ring pairs 42. The microprocessor 70in the controller 26 activates the microcontroller 48 of each sub-unit24 sequentially. Each microcontroller 48 enables each pair of electrodes56 and measures the electrode pair capacitance via the timer 46, whichconverts capacitance to a frequency. The result is that themicroprocessor 70 in the controller 26 initiates the reading ofcapacitance of every pair of electrodes 56 from top to bottom in theprobe 22 or 23, and determines whether the contents at each pair ofelectrodes 56 is FOG, water, sludge or air. The proximity of theelectrodes 56 against the surface of the probe 22 maximizes the electricfield in the interceptor interior and increases the precision of thecapacitance measurement.

Referring to FIG. 6, a block diagram of the controller 26 is shown. Thecontroller 26 provides the following three main functions for the probe22: (1) drives the frequency measurement of each sensor circuit 40 ₁-40₈. (2) determines the identity of the liquid content of an interceptor30 such as FOG, water, sludge and air of each sensor circuit 40 ₁-40 ₈,and (3) transmits the identity of each level through one of threewireless methods. This controller 26 is attached to a printed circuitboard which is referred to as the headboard 50. The controller 26comprises a microprocessor 70 and communicates with each of the sensorcircuits 40 ₁-40 ₈ via a serial bus interface 90. The microprocessor 70is programmed to instruct the microcontroller 48 in each sensor circuit40 to enable 50 the frequency output. The controller 26 communicates theresults of the interpreted frequency measurements to the wirelessinterface 74. The portable probe 23 uses Bluetooth low energy (BLE) 29and the fixed probe 22 uses the low radio frequency protocol LoRa 27 orThread. The wireless interface 74 is also used for control,configuration, and firmware updates.

Still referring to FIG. 6 an external switch 76 turns the controller 26,and therefore the probe 22 or 23, ON and OFF. The temperature sensor 72provides a temperature reading of the interceptor 30 environment. TheLED 78 provides status information to a user. The LED indicator 82provides a voltage reading of the LiPo battery 84 and the batterycharger 80 is controllable by the microprocessor 70 and power managementcircuit 88, and the power 86 provides voltages to the sensor circuits 40₁-40 ₈. The microprocessor 70 may be embodied by part number ESP32 byEsprssif, commonly known in the art.

For determining the fluid or material type in an interceptor 30, thecapacitance of each sensor circuits 40 ₁-40 ₈ or materials asrepresented by a frequency value is mapped to the identity of the fluidor materials at the sensor electrode ring pairs 42 as being either FOG,water, sludge or air. A lookup table, constructed through laboratorytesting, determines the range of frequencies appropriate for each typeof fluid or material. For differentiating more accurately between sludgeand water or between FOG and air, both pairs of fluids having verysimilar capacitance values, an algorithm based on the derivative offrequency values is used.

The probe data is embodied in a bar graph such as on a smart device 34that is divided into horizontal segments. Each segment corresponds toone sensor circuit 40 and is color coded to represent the identity ofthe material at that level including FOG, water, sludge or air. Thetotal volume of the interceptor 30 contents of FOG and sludge isexpressed as a fraction of the interceptor 30 contents. Most AuthoritiesHaving Jurisdiction (AHJ) mandate that this fraction be no greater than25%.

For the display and storage of data in a fixed probe 22, the headboardof the controller 26 of a fixed probe 22 also contains a radio thattransmits data either via the LoRa 27 or Thread communication protocol.The radio communicates to a transmitter mounted in the vicinity of thegrease interceptor, e.g. on a wall or in an office. The transmitterrelays the data to a Cloud-based file 32 via WiFi (802.11 protocol).

Referring to FIG. 7, the steps of the method 100 of capacitancemeasurements are as follows: Prior to a measurement all sensor circuits40 ₁-40 ₈ are powered OFF and in Step 102 power is turned ON. In Step104 the microprocessor 70 initializes the system. In Step 106 theselection of a sensor circuit 40 ₁-40 ₈ is made. The status lineswitches to HIGH for 1 millisecond (ms) then LOW for 1 ms and then staysHIGH. In Step 108 oscillations are allowed to stabilize.

In Step 110 the frequency measurement is made as follows: Themicrocontroller 48 switches the connection to the timer circuit for 4seconds. This timer 46 outputs a square wave on the frequency line 49.The status line switches to LOW for 1 ms then switches HIGH. Thissignals that the frequency of the sampling capacitor is to be measured.The microcontroller 48 switches the connection between the samplingcapacitor and timer 46 for 4 seconds. This outputs a square wave on thefrequency line 49. The frequency of the square wave is proportional tothe sample capacitance. The microprocessor 70 adds the values of thefrequency to a record.

In Step 112 the sensor circuit 40 address is incremented, and in Step114 it is determined if there is another sensor circuit, and if so theoperation returns to Step 106. Otherwise, the operation goes to Step 116and the measured data is sent to the server, and in Step 118 power isturned OFF. If the operation is returned to Step 106, then a secondmeasurement is made and the values added to the record. Themicroprocessor 70 continues this loop of Steps 106 to 114 until themicroprocessor 70 cannot find the next sensor circuit 40 ₁-40 ₈ at whichpoint it completes the record and transmits the data to the controller26.

The foregoing description of the embodiments of the invention has beenpresented for the purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed. Many modifications and variations are possible in light ofthis disclosure. It is intended that the scope of the invention belimited not by this detailed description, but rather by the claimsappended hereto.

What is claimed is:
 1. An analyzer for measuring levels of fats, oils,grease, (FOG) water, sludge and air in an interceptor comprising: aprobe having a first portion and a second portion; said first portion ofsaid probe comprises control means and communication means; said secondportion of said probe comprises at least one sensor sub-unit formeasuring said levels of FOG, water, sludge and air in said interceptor;said sensor sub-unit comprises a plurality of electrode ring pairspositioned adjacent to each other; a plurality of timers, each of saidtimers being coupled to each of said electrode ring pairs respectivelyin said sensor sub-unit for converting a capacitance measurement of eachof said electrode ring pairs to a frequency; and a controller, includedin said control means of said first portion of said probe, being coupledto each frequency output of each of said timers for determining saidlevels of FOG, water, sludge and air in said interceptor.
 2. Theanalyzer as recited in claim 1 wherein a microcontroller in said sensorsub-unit and in response to said controller enables said capacitancemeasurements to be made in a sequential manner by each of said timersconnected to each of said electrode ring pairs.
 3. The analyzer asrecited in claim 1 wherein said first portion of said probe comprises anenclosure into which said second portion is secured.
 4. The analyzer asrecited in claim 3 wherein said electrode ring pairs are positionedwithin said sub-unit immediately adjacent to an inside surface of saidenclosure.
 5. The analyzer as recited in claim 1 wherein each of saidelectrode ring pairs comprises two adjacent copper strips sandwichedbetween sheets of plastic and positioned within a sensor sub-unit in acircular formation forming plates of a capacitor, a dielectric of saidcapacitor being formed by substances within an influence of an electricfield generated by said plates.
 6. The analyzer as recited in claim 1wherein said controller determines said FOG, water, sludge, and airlevels in said interceptor, and transmits said levels to an externalreceiver.
 7. The analyzer as recited in claim 6 wherein an identity ofmaterials including FOG, water, sludge and air at a level of eachelectrode ring pair is determined by an algorithm in a microprocessor ofsaid controller.
 8. The analyzer as recited in claim 7 wherein saidalgorithm determines said identity of said materials including FOG,water, sludge and air at said levels of each of said electrode ringpairs, from the value of said frequencies.
 9. The analyzer as recited inclaim 7 wherein said algorithm determines the identity of the materialsincluding FOG, water, sludge and air at said level of each saidelectrode ring pair from a function of a range of frequencies of saidelectrode ring pair and adjacent electrodes.
 10. The analyzer as recitedin claim 1 wherein said probe comprises a fixed probe when attached tosaid interceptor, and communicates identity of said FOG, water, sludgeand air levels via a low frequency radio signal to a receiver.
 11. Theanalyzer as recited in claim 1 wherein said probe comprises a portableprobe for temporary insertion into said interceptor, and said portableprobe communicates identity of said FOG, water, sludge and air levelsvia Bluetooth Le to an external device.
 12. The analyzer as recited inclaim 1 wherein said length of said probe is determined by the number ofsaid sub-units daisy chained, one adjacent to another, each of saidsub-units comprises a plurality of said electrode ring pairs coupled toa plurality of said timers and including a microcontroller for enablingsaid capacitance measurement by each of said timers in a sequentialmanner.
 13. A sensor sub-unit of an analyzer for measuring levels offats, oils, grease, (FOG) water, sludge and air in an interceptorcomprising: a plurality of electrodes positioned adjacent to each otherin a circular arrangement; terminals of said electrodes are attached toa printed circuit board (PCB) and positioned within said circulararrangement of said electrodes; a plurality of timers positioned on saidPCB, each of said timers receives an input from one pair of saidplurality of electrodes forming a plurality of electrode ring pairs; andsaid plurality of timers convert a capacitance measurement at each ofsaid plurality of electrode ring pairs to a frequency.
 14. The sensorsub-unit as recited in claim 13 wherein said electrodes comprisemetallic electrodes.
 15. The sensor sub-unit as recited in claim 13wherein a microcontroller enables a readout of a capacitance measurementsequentially from an output of each said plurality of timers.
 16. Thesensor sub-unit as recited in claim 15 wherein a controller receivessaid capacitance measurement from each of said plurality of timers anddetermines an identity of said levels of FOG, water, sludge, and air insaid interceptor.
 17. The sensor sub-unit as recited in claim 13 whereineach end of said sub-unit comprises a means for connecting sensorsub-units in a daisy chain arrangement, one sub-unit connected to anadjacent sub-unit, for enabling said capacitor measurement to be made ina plurality of interceptors of varying heights.
 18. A method for makingan analyzer for measuring levels of fats, oils, grease, (FOG) water,sludge, and air in an interceptor comprising the steps of: providing aprobe having a first portion which comprises control means andcommunication means; providing a second portion of said probe having atleast one sensor sub-unit for measuring said levels of FOG, water,sludge, and air in said interceptor; positioning in said sensor sub-unita plurality of electrode ring pairs adjacent to each other in a circulararrangement; converting a capacitance measurement of each of saidplurality of electrode ring pairs to a frequency using a plurality oftimers, each of said timers being coupled to each of said plurality ofelectrode ring pairs respectively in said sensor sub-unit; determiningan identity of said levels of FOG, water, sludge and air in saidinterceptor using a controller, said controller being included in saidcontrol means of said first portion of said probe coupled to eachfrequency output of each of said timers.
 19. The method as recited inclaim 18 comprises the step of enabling said capacitance measurement tobe made in a sequential manner by each of said timers connected to eachof said electrode ring pairs using a microcontroller in said sensorsub-unit and in response to a signal from said controller.
 20. Themethod as recited in claim 18 comprises the step of positioning saidelectrode ring pairs within said sub-unit immediately adjacent to aninside surface of said first portion of a probe.
 21. The method asrecited in claim 18 comprises the step of forming plates of a capacitorwherein each of said electrode ring pairs comprises two adjacent metalstrips sandwiched between sheets of plastic and positioned within saidsensor sub-unit in said circular arrangement, a dielectric of saidcapacitor being formed by substances within an influence of an electricfield generated by said plates.
 22. The method as recited in claim 18comprises the step of using said controller to determine an identity ofsaid FOG, water, sludge, and air in said interceptor, and transmittingsaid identity to an external receiver.
 23. The method as recited inclaim 22 comprises the step of representing by a range of frequenciesreceived from said timer, said identity of each of said FOG, water,sludge and air levels, and an algorithm in a microprocessor of saidcontroller determines said FOG, water, sludge and air levels identityfrom said range of frequencies.
 24. The method as recited in claim 18wherein said method comprises the step of determining said length ofsaid probe by the number of said sub-units daisy chained, one adjacentto another, each of said sub-units comprises a plurality of saidelectrode ring pairs coupled to a plurality of said timers and includinga microcontroller for enabling said capacitance measurement by each ofsaid timers in a sequential manner.